The obesity paradox in the surgical population

The Association of Body Mass Index and Early Outcomes Following Orthognathic Surgery

BACKGROUND

The existing data on the link between body mass index (BMI), operative characteristics, and surgical outcomes across orthognathic surgery are limited.

PURPOSE

The purpose was to measure the association between BMI and early postoperative outcomes in orthognathic surgery.

STUDY DESIGN, SETTING, AND SAMPLE

This is a retrospective cohort study of patients (n = 118) aged > 14 years undergoing bimaxillary orthognathic surgery between 2015 and 2018 by a single surgeon within the Kaiser Permanente Northern California-integrated healthcare system. Patients undergoing unilateral or additional procedures, history of prior orthognathic surgery, or pre-existing pain conditions were excluded.

PREDICTOR VARIABLE

The predictor variable was BMI measured as a continuous (kg/m2) and categorical variable (underweight/normal, overweight, obese).

MAIN OUTCOME VARIABLE(S)

The primary outcome variables were additional postoperative antibiotics, increased postoperative visits, wound dehiscence, and wound infection. The secondary outcome variables were total operative and anesthesia time.

COVARIATES

The demographic covariates included age, sex, and race/ethnicity. The clinical covariates included history of obstructive sleep apnea, Mallampati score, tobacco use, American Society of Anesthesia classification, thyromental distance, history of difficult intubation, and Angle's classification.

ANALYSES

Bivariate and multivariate analyses were performed to measure the associations between BMI and the primary and secondary outcomes. Multivariable logistic regression analyses were used to measure associations between BMI and the postoperative outcomes. Statistical significance was defined as P < .05.

RESULTS

The study sample was composed of 118 subjects with a mean age of 26.91 years (standard deviation 9.43). Forty-seven percent (n = 55) were male, and the mean BMI was 25.13 (standard deviation 5.19). BMI category was significantly associated with age, with increasing age associated with higher BMI category (P = .02). According to the bivariate and multivariable logistic regression analyses, controlling for age, race/ethnicity, BMI, and total operative time, increased total operative time was associated with additional postoperative antibiotics (odds ratio = 1.03, 95% confidence interval: 1.01, 1.05), and increased postoperative appointments (odds ratio = 1.02, 95% confidence interval: 1.01, 1.04). No significant association between BMI and other clinical or operative characteristics was seen aside from American Society of Anesthesia classification.

CONCLUSION AND RELEVANCE

Elevated BMI was not associated with worsened operative characteristics or postoperative outcomes. This supports the suitability of orthognathic surgery in a BMI-diverse population.

Debunking the "Obesity Paradox": Obesity is Associated With Adverse Outcomes in Emergency General Surgery

INTRODUCTION

Obesity is increasingly prevalent both nationwide and in the emergency general surgery (EGS) population. While previous studies have shown that obesity may be protective against mortality following EGS procedures, the association between body mass index (BMI) and postoperative outcomes, as well as intraoperative decision-making, remains understudied.

METHODS

The National Surgical Quality Improvement Program 2015-2019 database was used to identify all adult patients undergoing an open abdominal or abdominal wall procedure for EGS conditions. Our outcomes included 30-d postoperative mortality, composite 30-d morbidity, delayed fascial closure, reoperation, operative time, and hospital length of stay (LOS). Multivariable logistic regression models were used to explore the association between BMI and each outcome of interest while adjusting for patient demographics, comorbidities, laboratory tests, preoperative and intraoperative variables.

RESULTS

We identified 78,578 patients, of which 3121 (4%) were categorized as underweight, 23,661 (30.1%) as normal weight, 22,072 (28.1%) as overweight, 14,287 (18.2%) with class I obesity, 7370 (9.4%) with class II obesity, and 8067 (10.3%) with class III obesity. Class III obesity was identified as a risk factor for 30-d postoperative morbidity (adjusted odds ratio 1.14, 95% CI, 1.03-1.26, P < 0.01). An increase in obesity class was also associated with a stepwise increase in the risk of undergoing delayed fascial closure, experiencing a prolonged operative time, and having an extended LOS.

CONCLUSIONS

Obesity class was associated with an increase in delayed fascial closure, longer operative time, higher reoperation rates, and extended hospital LOS. Further studies are needed to explore how a patient's BMI impacts intraoperative factors, influences surgical decision-making, and contributes to hospital costs.

Surgical Complications Following Renal Transplantation in a Large Institutional Cohort

Background

Successful renal transplantation (RTx) relies on immunosuppression and an optimal surgical course with few surgical complications. Studies reporting the postoperative complications after RTx are heterogeneous and often lack systematic reporting of complications. This study aims to describe and identify postoperative short-term and long-term complications after RTx in a large institutional cohort and identify risk factors for a complicated surgical course.

Methods

The study is a retrospective single-center cohort of 571 recipients who underwent living or deceased donor open RTx between 2014 and 2021. Data were collected on background information and perioperative and postoperative data. Complications were defined as short-term (<30 d) or long-term (>30 d) after transplantation and graded according to the Clavien-Dindo classification. Multivariable logistic regression was performed to evaluate risk factors for serious short-term complications and multivariable time-dependent Cox regression to evaluate risk factors for long-term complications.

Results

A total of 351 patients received a graft from a deceased donor, and 144 of these grafts were on perfusion machine before transplantation. One or more short-term complications occurred in 345 (60%) patients. Previous RTx was associated with short-term Clavien-Dindo >2 complications in recipients (odds ratio = 2.08; 95% confidence interval [CI], 1.18-3.69; P = 0.01). Being underweight (body mass index <18.5) in combination with increasing age increased the odds of short-term Clavien-Dindo >2 and vascular complications. Increasing blood loss per 100 mL was associated with increased odds of short-term Clavien-Dindo >2 (odds ratio = 1.11; 95% CI, 1.01-1.21; P = 0.032). No associations were found for long-term complications after RTx. The 5-y cumulative incidence of graft loss was 12.6% (95% CI, 8.9-16.3).

Conclusions

Short-term complications are common after RTx, and risk factors for severe short-term complications include previous RTx, increasing age, and low body mass index. No risk factors were identified for severe long-term complications. Further studies should explore whether new surgical techniques can reduce surgical complications in RTx.

The obesity paradox exists for perioperative complications and mortality following lower extremity arterial bypass surgery

OBJECTIVE

The obesity paradox refers to a phenomenon by which obese individuals experience lower risk of mortality and even protective associations from chronic disease sequelae when compared with the non-obese and underweight population. Prior literature has demonstrated an obesity paradox after cardiac and other surgical procedures. However, the relationship between body mass index (BMI) and perioperative complications for patients undergoing major open lower extremity arterial revascularization is unclear.

METHODS

We queried the Vascular Quality Initiative for individuals receiving unilateral infrainguinal bypass between 2003 and 2020. We used multivariable logistic regression to assess the relationship of BMI categories (underweight [<18.5 kg/m2], non-obese [18.5-24.9 kg/m2], overweight [25-29.9 kg/m2], Class 1 obesity [30-34.9 kg/m2], Class 2 obesity [35-39.9 kg/m2], and Class 3 obesity [>40 kg/m2]) with 30-day mortality, surgical site infection, and adverse cardiovascular events. We adjusted the models for key patient demographics, comorbidities, and technical and perioperative characteristics.

RESULTS

From 2003 to 2020, 60,588 arterial bypass procedures met inclusion criteria for analysis. Upon multivariable logistic regression with the non-obese category as the reference group, odds of 30-day mortality were significantly decreased among the overweight (odds ratio [OR], 0.64; 95% confidence interval [CI], 0.53-0.78), Class 1 obese (OR, 0.65; 95% CI, 0.52-0.81), Class 2 obese (OR, 0.66; 95% CI, 0.48-0.90), and Class 3 obese (OR, 0.61; 95% CI, 0.39-0.97) patient categories. Conversely, odds of 30-day mortality were increased in the underweight patient group (OR, 1.58; 95% CI, 1.16-2.13). Furthermore, a BMI-dependent positive association was present, with odds of surgical site infections with patients in Class 3 obesity having the highest odds (OR, 2.10; 95% CI, 1.60-2.76). Finally, among the adverse cardiovascular event outcomes assessed, only myocardial infarction (MI) demonstrated decreased odds among overweight (OR, 0.82; 95% CI, 0.71-0.96), Class 1 obese (OR, 0.78; 95% CI, 0.65-0.93), and Class 2 obese (OR, 0.66; 95% CI, 0.51-0.86) patient populations. Odds of MI among the underweight and Class 3 obesity groups were not significant.

CONCLUSIONS

The obesity paradox is evident in patients undergoing lower extremity bypass procedures, particularly with odds of 30-day mortality and MI. Our findings suggest that having higher BMI (overweight and Class 1-3 obesity) is not associated with increased mortality and should not be interpreted as a contraindication for lower extremity arterial bypass surgery. However, these patients should be under vigilant surveillance for surgical site infections. Finally, patients that are underweight have a significantly increased odds of 30-day mortality and may be more suitable candidates for endovascular therapy.

Nomogram for predicting postoperative pulmonary complications in spinal tumor patients

OBJECTIVES

Although several independent risk factors for postoperative pulmonary complications (PPCs) after spinal tumor surgery have been studied, a simple and valid predictive model for PPC occurrence after spinal tumor surgery has not been developed.

PATIENTS AND METHODS

We collected data from patients who underwent elective spine surgery for a spinal tumor between 2013 and 2020 at a tertiary hospital in China. Data on patient characteristics, comorbidities, preoperative examinations, intraoperative variables, and clinical outcomes were collected. We used univariable and multivariable logistic regression models to assess predictors of PPCs and developed and validated a nomogram for PPCs. We evaluated the performance of the nomogram using the area under the receiver operating characteristic curve (ROC), calibration curves, the Brier Score, and the Hosmer-Lemeshow (H-L) goodness-of-fit test. For clinical use, decision curve analysis (DCA) was conducted to identify the model's performance as a tool for supporting decision-making.

RESULTS

Among the participants, 61 (12.4%) individuals developed PPCs. Clinically significant variables associated with PPCs after spinal tumor surgery included BMI, tumor location, blood transfusion, and the amount of blood lost. The nomogram incorporating these factors showed a concordance index (C-index) of 0.755 (95% CI: 0.688-0.822). On internal validation, bootstrapping with 1000 resamples yielded a bias-corrected area under the receiver operating characteristic curve of 0.733, indicating the satisfactory performance of the nomogram in predicting PPCs. The calibration curve demonstrated accurate predictions of observed values. The decision curve analysis (DCA) indicated a positive net benefit for the nomogram across most predicted threshold probabilities.

CONCLUSIONS

We have developed a new nomogram for predicting PPCs in patients who undergo spinal tumor surgery.

Prevalence and long-term implications of preoperative anemia in patients undergoing elective general surgery: a retrospective cohort study at a university hospital

OBJECTIVE

The aim of this retrospective study was to assess the prevalence of anaemia in a cohort of patients undergoing elective general surgery at a university hospital. Furthermore, the authors investigated the influence of anaemia on short-term and long-term postoperative outcome.

BACKGROUND

Awareness of the negative impact of preoperative anaemia on perioperative morbidity and mortality is rising. Anaemia is a potentially modifiable factor, and its therapy might improve patient outcome in elective surgery. Nevertheless, patients with preoperative anaemia frequently undergo elective surgery without receiving adequate preoperative treatment.

METHODS

In this single-centre cohort study, the authors analyzed 6908 adult patients who underwent elective general surgery. Patients undergoing day-clinic surgery were excluded. In all patients, preoperative haemoglobin concentration and haematocrit was available.

RESULTS

Of all patients analyzed, 32.9% were anaemic (21.0% mild, 11.8% moderate, 1.1% severe). Median time to last follow-up was 5.2 years. During the whole study period, 27.1% of patients died (1.2% died during the hospital stay); median time to death was 1.3 years. Patients with preoperative anaemia had significantly higher mortality rates ( P <0.001) and a higher probability of postoperative complications ( P <0.001). Likewise, receiving blood transfusions was associated with a higher risk of death ( P <0.001).

CONCLUSION

This retrospective single-centre analysis confirmed that preoperative anaemia is common, and is a significant risk factor for unfavourable postoperative outcome. As anaemia is a modifiable risk factor, the implementation of a patient blood management concept is crucial to reduce detrimental postoperative events associated with anaemia.

J147 affects cognition and anxiety after surgery in Zucker rats

Vulnerable patients are at risk for neuroinflammation-mediated post-operative complications, including depression (POD) and cognitive dysfunction (POCD). Zucker rats, expressing multiple risk factors for post-operative complications in humans, may provide a clinically relevant model to study pathophysiology and explore potential interventions. J147, a newly developed anti-dementia drug, was shown to prevent POCD in young healthy rats, and improved early post-surgical recovery in Zucker rats. Aim of the present study was to investigate POCD and the therapeutic potential of J147 in male Zucker rats. Risk factors in the Zucker rat strain were evaluated by comparison with lean littermates. Zucker rats were subjected to major abdominal surgery. Acute J147 treatment was provided by a single iv injection (10 mg/kg) at the start of surgery, while chronic J147 treatment was provided in the food (aimed at 30 mg/kg/day), starting one week before surgery and up to end of protocol. Effects on behavior were assessed, and plasma, urine and brain tissue were collected and processed for immunohistochemistry and molecular analyses. Indeed, Zucker rats displayed increased risk factors for POCD, including obesity, high plasma triglycerides, low grade systemic inflammation, impaired spatial learning and decreased neurogenesis. Surgery in Zucker rats reduced exploration and increased anxiety in the Open Field test, impaired short-term spatial memory, induced a shift in circadian rhythm and increased plasma neutrophil gelatinase-associated lipocalin (NGAL), microglia activity in the CA1 and blood brain barrier leakage. Chronic, but not acute J147 treatment reduced anxiety in the Open Field test and protected against the spatial memory decline. Moreover, chronic J147 increased glucose sensitivity. Acute J147 treatment improved long-term spatial memory and reversed the circadian rhythm shift. No anti-inflammatory effects were seen for J147. Although Zucker rats displayed risk factors, surgery did not induce extensive POCD. However, increased anxiety may indicate POD. Treatment with J147 showed positive effects on behavioral and metabolic parameters, but did not affect (neuro)inflammation. The mixed effect of acute and chronic treatment may suggest a combination for optimal treatment.

The causes of death in patients with nonalcoholic steatohepatitis following liver transplantation stratified using pre-liver transplant BMI

BACKGROUND & AIMS

Determining the effects of pre-liver transplant (LT) BMI independent of underlying ascites on the post-LT outcomes of patients with nonalcoholic steatohepatitis (NASH) is needed to clarify the paradoxical and protective effects of obesity on post-LT endpoints. In order to accomplish this, we used graded severities of ascites to stratify the NASH-LT population and to perform an ascites-specific strata analysis with differing pre-LT BMI levels.

METHODS

2005-2019 United Network for Organ Sharing (UNOS) Standard Transplant Analysis and Research (STAR) database was queried to select patients with NASH, who were categorized into specific sets of ascites severity: no ascites (n = 1188), mild ascites (n = 4463), and moderate ascites (n = 3525). Then, BMI classification (underweight: < 18.5, normal: 18.5-25, overweight: 25-30, obese: ≥ 30 kg/m2) was used to stratify each ascites-specific group and to compare to the post-LT mortality endpoints. Those under 18 years old and those who received living/multi-organ transplants were excluded.

RESULTS

Among each ascites category, there were the following numbers of normal, underweight, overweight, and obese BMI patients respectively; no ascites: 161, 4, 359, 664; mild ascites: 643, 28, 1311, 2481; and moderate ascites: 529, 25, 1030, 1941. The obese BMI cohort was at a lower risk of all-cause mortality compared to recipients with normal BMI with mild ascites (aHR: 0.79, 95% Confidence Interval (CI) 0.65-0.94, p-value = 0.010; case-incidence 47.10 vs 56.81 deaths per 1000 person-years) and moderate ascites (aHR: 0.77, 95% CI 0.63-0.94, p-value = 0.009; case-incidence 53.71 vs 66.17 deaths per 1000 person-years). In addition, the overweight BMI cohort with mild ascites demonstrated a lower hazard of all-cause mortality (aHR: 0.80, 95% CI 0.66-0.97, p-value = 0.03; case-incidence 49.09 vs 56.81 deaths per 1000 person-years). There was no difference in graft failure for the three BMI groups (underweight, overweight, and obese) in comparison to normal BMI. Furthermore, the overweight BMI group with mild ascites cohort demonstrated a lower hazard of death due to general infectious causes (aHR: 0.51, 95% CI 0.32-0.83, p = 0.006; case-incidence 6.12 vs 11.91 deaths per 1000 person-years) and sepsis (aHR: 0.49, 95% CI 0.27-0.86, p = 0.01; case-incidence 4.31 vs 8.50 deaths per 1000 person-years).

CONCLUSION

The paradoxical effects of obesity in reducing the risks of all-cause death appears to be in part modulated by ascites. The current study emphasizes the need to evaluate BMI with concomitant ascites severity pre-LT to accurately prognosticate post-LT outcomes when evaluating NASH patients with advanced liver disease.

Development and External Validation of a Nomogram Including Body Composition Parameters for Predicting Early Recurrence of Hepatocellular Carcinoma After Hepatectomy

RATIONALE AND OBJECTIVES

Body composition, including adipose and muscle tissues, evaluated by computer tomography is correlated with the prognosis of hepatocellular carcinoma (HCC). However, its relationship with early recurrence (ER) remains unclear. This study aimed at establishing and validating a nomogram based on body composition and clinicopathological indices to predict ER of HCC.

MATERIALS AND METHODS

One hundred ninety-five patients from institution A formed the training cohort and internal validation cohort, and 50 patients from institution B formed the external validation cohort. Independent predictors of ER were identified using LASSO and Cox regression analyses. The performance of nomogram was evaluated using the calibration curve, concordance index (C-index), area under the curve (AUC), and decision curve analysis (DCA).

RESULTS

After data screening, the nomogram was constructed using eight independent predictors of ER, including the tumor size, alpha fetoprotein, body mass index, Edmondson Steiner grade, visceral adipose tissue radiodensity, intermuscular adipose tissue index, intramuscular adipose tissue content, and skeletal muscle area. The calibration curve exhibited excellent concordances, with C-indices of 0.808 (95%CI: 0.771-0.860), 0.802 (95%CI: 0.747-0.942), and 0.804 (95%CI: 0.701-0.861) in training, internal validation, and external validation cohorts, respectively. In addition, compared to conventional staging systems and pure clinical model, the nomogram exhibited a higher AUC and wider range of threshold probabilities in DCA, which indicated better discriminative ability and greater clinical benefit. Finally, patients with nomogram scores of <183.07, 183.07-243.09, and >243.09 were considered to have low, moderate, and high risks of ER, respectively.

CONCLUSION

The nomogram exhibits excellent ER predictive ability for patients with HCC who underwent hepatectomy.

The effect of body mass index and preoperative weight loss in people with obesity on postoperative outcomes to 6 months following total hip or knee arthroplasty: a retrospective study

BACKGROUND

Few studies have investigated the association between obesity, preoperative weight loss and postoperative outcomes beyond 30- and 90-days post-arthroplasty. This study investigated whether body mass index (BMI) and preoperative weight loss in people with obesity predict postoperative complications and patient-reported outcomes 6 months following total knee or hip arthroplasty.

METHODS

Two independent, prospectively collected datasets of people undergoing primary total knee or hip arthroplasty for osteoarthritis between January 2013 and June 2018 at two public hospitals were merged. First, the sample was grouped into BMI categories, < 35 kg/m2 and ≥ 35 kg/m2. Subgroup analysis was completed separately for hips and knees. Second, a sample of people with BMI ≥ 30 kg/m2 was stratified into participants who did or did not lose ≥ 5% of their baseline weight preoperatively. The presence of postoperative complications, Oxford Hip Score, Oxford Knee Score, EuroQol Visual Analogue Scale and patient-rated improvement 6 months post-surgery were compared using unadjusted and adjusted techniques.

RESULTS

From 3,552 and 9,562 patients identified from the datasets, 1,337 were included in the analysis after merging. After adjustment for covariates, there was no difference in postoperative complication rate to 6 months post-surgery according to BMI category (OR 1.0, 95%CI 0.8-1.4, P = 0.8) or preoperative weight loss (OR 1.1, 95%CI 0.7-1.8, P = 0.7). There was no between-group difference according to BMI or preoperative weight change for any patient-reported outcomes 6 months post-surgery.

CONCLUSION

Preoperative BMI or a 5% reduction in preoperative BMI in people with obesity was not associated with postoperative outcomes to 6 months following total knee or hip arthroplasty.

Moving beyond frailty: Obesity paradox persists in lung resection

BACKGROUND

The apparent protective effect of high body mass index on postoperative outcomes, termed the "obesity paradox," has been postulated to reflect the relative frailty of patients without obesity. We wanted to examine the independent association between body mass index and outcomes after anatomic lung resection.

METHODS

All adults undergoing elective lung resection for cancer were identified in the 2012-2020 National Surgical Quality Improvement Program. The modified Frailty Index quantified degree of patient frailty. Malnutrition was defined as a preoperative serum albumin <3.5g/dL. Multivariable regressions were used to examine the independent association of body mass index and major adverse events, analyzed as a composite of 30-day mortality, postoperative complications, and unplanned reoperation.

RESULTS

Of an estimated 20,099 patients meeting study criteria, 6,424 (32.0%) had obesity. Relative to others, patients with obesity were significantly younger (49.3 vs 50.3 years), more commonly White (78.1 vs 74.9%), and more frequently frail (modified Frailty Index >1: 35.7 vs 22.5%, all P < .001). There was no significant difference in malnutrition rates (7.6 vs 8.4%, P = .05) or extent of resection between groups. After adjustment, obesity was associated with decreased odds of major adverse events (adjusted odds ratio 0.86, 95% confidence interval 0.78-0.94).

CONCLUSION

The present findings uphold the canonical obesity paradox in anatomic lung resection, despite adjustment for frailty and malnutrition. Further studies are warranted to characterize the nature of this association; however, our results may inform efforts to optimize risk stratification and patient selection for surgical intervention.

The surgical patient of yesterday, today, and tomorrow-a time-trend analysis based on a cohort of 8.7 million surgical patients

BACKGROUND

Global healthcare delivery is challenged by the aging population and the increase in obesity and type 2 diabetes. The extent to which such trends affect the cohort of patients the authors surgically operate on remains to be elucidated. Comprising of 8.7 million surgical patients, the American College of Surgeons (ACS) National Surgical Quality Improvement Program (NSQIP) database can be analyzed to investigate the echo of general population dynamics and forecast future trends.

MATERIAL AND METHODS

The authors reviewed the ACS-NSQIP database (2008-2020) in its entirety, extracting patient age, BMI, and diabetes prevalence. Based on these data, the authors forecasted future trends up to 2030 using a drift model.

RESULTS

During the review period, median age increased by 3 years, and median BMI by 0.9 kg/m2. The proportion of patients with overweight, obesity class I, and class II rates increased. The prevalence of diabetes rose between 2008 (14.9%) and 2020 (15.3%). The authors forecast the median age in 2030 to reach 61.5 years and median BMI to climb to 29.8 kg/m2. Concerningly, in 2030, eight of ten surgical patients are projected to have a BMI above normal. Diabetes prevalence is projected to rise to 15.6% over the next decade.

CONCLUSION

General population trends echo in the field of surgery, with the surgical cohort aging at an alarmingly rapid rate and increasingly suffering from obesity and diabetes. These trends show no sign of abating without dedicated efforts and call for urgent measures and fundamental re-structuring for improved future surgical care.

Elevated Body Mass Index Associated with Cerebrospinal Fluid Leak after Lateral Skull Base Surgery: A Systematic Review and Meta-analysis

OBJECTIVE

To determine if body mass index (BMI) increases the risk of cerebrospinal fluid (CSF) leak after lateral skull base surgery.

DATA SOURCES

CINAHL, PubMed, and Scopus were searched from January 2010 to September 2022 for articles published in English.

STUDY SELECTION

Articles that reported BMI or obesity with and without CSF leaks after lateral skull base surgery were included.

DATA EXTRACTION

Two reviewers (F.G.D. and B.K.W.) independently performed study screening, data extraction, and risk of bias assessment.

DATA SYNTHESIS

A total of 11 studies and 9,132 patients met inclusion criteria. Meta-analysis of mean difference (MD), odds ratio (OR), proportions, and risk ratio (RR) were calculated using RevMan 5.4 and MedCalc 20.110. BMI for patients with CSF leak after lateral skull base surgery (29.39 kg/m2, 95% confidence interval [CI] = 27.75 to 31.04) was significantly greater than BMI for patients without CSF leak after lateral skull base surgery (27.09 kg/m2, 95% CI = 26.16 to 28.01) with an MD of 2.21 kg/m2 (95% CI = 1.09 to 3.34, p = 0.0001). The proportion of patients with BMI ≥ 30 kg/m2 that had a CSF leak was 12.7%, and the proportion of patients with BMI < 30 kg/m2 (control) that had a CSF leak was 7.9%. The OR for CSF leak after lateral skull base surgery in patients with BMI ≥ 30 kg/m2 was 1.94 (95% CI = 1.40 to 2.68, p < 0.0001), and the RR was 1.82 (95% CI = 1.36 to 2.43, p < 0.0001).

CONCLUSION

Elevated BMI increases the risk of CSF leak after lateral skull base surgery.

LEVEL OF EVIDENCE

IIa.

A Comparison of the Charlson and Elixhauser Methods for Predicting Nursing Indicators in Gastrectomy with Gastric Cancer Patients

Background: Comorbidity indices such as Charlson's (CCI) and Elixhauser's (ECI) are used to adjust the patient's care, depending on the severity of their condition. However, no study has compared these indices' ability to predict nursing-sensitive outcomes (NSOs). We compared the performance of CCI and ECI in predicting NSOs in gastric cancer patients' gastrectomy. Methods: Gastric cancer patients with gastrectomy, aged 19 years or older and admitted between 2015 and 2016, were selected from the Korea Insurance Review and Assessment Service database. We examined the relationships between NSOs and CCI or ECI while adjusting patient and hospital characteristics with logistic regression. Results: The ECI item model was the best in view of the C-statistic and Akaike Information Criterion for total NSO, physiologic/metabolic derangement, and deep vein thrombosis, while the Charlson item model was the best for upper gastrointestinal tract bleeding. For the C-statistic, the ECI item model was the best for in-hospital mortality, CNS complications, shock/cardiac arrest, urinary tract infection, pulmonary failure, and wound infection, while the CCI item model was the best for hospital-acquired pneumonia and pressure ulcers. Conclusions: In predicting 8 of 11 NSOs, the ECI item model outperformed the others. For other NSOs, the best model varies between the ECI item and CCI item model.

Impact of elevated body mass index on burn injury-associated mortality in a representative US sample

BACKGROUND

The impact of obesity on burn-related mortality is inconsistent and incongruent; despite being a risk factor for numerous comorbidities that would be expected to increase complications and worsen outcomes, there is evidence of a survival advantage for patients with high body mass index-the so-called obesity paradox. We used a national data set to explore further the relationship between body mass index and burn-related mortality.

METHODS

Deidentified data from patients with second and third-degree burns between 2014 and 2018 were obtained from the Cerner Health Facts Database. Univariate and multivariate regression models were created to identify potential factors related to burn-related mortality. A restricted cubic spline model was built to assess the nonlinear association between body mass index and burn-related mortality. All statistical analyses were conducted using R (R Foundation for Statistical Computing).

RESULTS

The study included 9,405 adult burn patients. Univariate and multivariate analyses revealed that age (odds ratio = 2.189 [1.771, 2.706], P < .001), total burn surface area (odds ratio = 1.824 [1.605, 2.074], P < .001), full-thickness burns (odds ratio = 1.992 [1.322, 3.001], P < .001), and comorbidities (odds ratio = 2.03 [1.367, 3.014], P < .001) were associated with increased mortality. Sensitivity analysis showed similar results. However, a restricted cubic spline indicated a U-shaped relation between body mass index and burn-related mortality. The nadir of body mass index was 28.92 kg/m², with the lowest mortality. This association persisted even after controlling for age, total burn surface area, full-thickness burns, and comorbidities, which all remained significant.

CONCLUSION

This study confirms a U-shaped association between body mass index and burn-related mortality along with age, total burn surface area, full-thickness burns, and comorbidities as risk factors.

Consequences of Obesity on Short-Term Outcomes in Patients Who Underwent Off-Pump Coronary Artery Bypass Grafting Surgery

The correlation between off-pump coronary artery bypass (OPCAB) surgery and obesity-related outcomes is still uncertain. The aim of our study was to analyse the pre-, intra-, and postoperative short-term outcomes between obese and non-obese patients after off-pump bypass surgery. We performed a retrospective analysis from January 2017 until November 2022, including a total of 332 (non-obese (n = 193) and obese (n = 139)) patients who underwent an OPCAB procedure due to coronary artery disease (CAD). The primary outcome was all-cause in-hospital mortality. Our results showed no difference regarding mean age of the study population between both groups. The use of the T-graft technique was significantly higher (p = 0.045) in the non-obese group compared to the obese group. The dialysis rate was significantly lower in non-obese patients (p = 0.019). In contrast, the wound infection rate was significantly higher (p = 0.014) in the non-obese group compared to the obese group. The all-cause in-hospital mortality rate did not differ significantly (p = 0.651) between the two groups. Furthermore, ST-elevation myocardial infarction (STEMI) and reoperation were relevant predictors for in-hospital mortality. Therefore, OPCAB surgery remains a safe procedure even in obese patients.

Risk assessment of postoperative pneumonia in children with neurologic disorders and obesity

INTRODUCTION

Postoperative pneumonia increases the risk of postsurgical mortality, making it a serious healthcare-associated complication. Children with preoperative neuromuscular impairments have a higher risk of postoperative pneumonia. Obesity is also a risk factor for postoperative pulmonary complications, including pneumonia. Moreover, obesity is increasingly prevalent among children living with a neurological diagnosis. Whether obesity increases the risk of postoperative pneumonia among children with neurologic diseases remains largely unknown. Therefore, we assessed the risk of postoperative pneumonia among children with neurologic diagnoses based on their obesity status.

METHODS

We analyzed a retrospective cohort of children ≤18 years from the National Surgical Quality Improvement Program (2012-2019) database who underwent inpatient orthopedic surgery. We used Cox proportional regression model to estimate the hazard ratio for the association between neurologic disorders and postoperative pneumonia. In addition, we included an interaction term between body mass index and neurologic disorders to evaluate the moderating effect of obesity status and then performed stratified analyses to compare the magnitude of hazard ratios across body mass index subgroups.

RESULTS

A total of 60 745 children underwent inpatient orthopedic surgery during the study period, of whom 43.6% were healthy weight and 30.8% overweight/obese. The median age was 13 years (Interquartile range: 8-15). The incidence of postoperative pneumonia was higher among healthy weight patients with neurologic disorders than healthy weight patients without any neurologic disorders [Hazard ratio: 3.55 vs. 0.34]. Furthermore, the association between neurologic disorders and postoperative pneumonia was strongest among overweight patients than healthy weight or obese patients [Hazard ratio:11.88 vs. 9.45 vs. 4.40]. This observation was consistent across the various neurologic disorders analyzed.

CONCLUSION

Childhood obesity buffered the association between neurologic disorders and postoperative pneumonia, consistent with an 'obesity paradox'. Further research exploring the underlying mechanisms for the obesity paradox in children with neurologic disorders is warranted.

Impact of Obesity on Early In-Hospital Outcomes after Coronary Artery Bypass Grafting Surgery in Acute Coronary Syndrome: A Propensity Score Matching Analysis

Recent advances in perioperative care have considerably improved outcomes after coronary artery bypass graft (CABG) surgery. However, obesity can increase postoperative complication rates and can lead to increased morbidity and mortality. Between June 2011 and October 2019, a total of 1375 patients with acute coronary syndrome (ACS) underwent cardiac surgery and were retrospectively analyzed. Patients were divided into 2 groups: non-obese (body mass index (BMI) < 30 kg/m2, n = 967) and obese (BMI ≥ 30 kg/m2, n = 379). Underweight patients (n = 29) were excluded from the analysis. To compare the unequal patient groups, a propensity score-based matching (PSM) was applied (non-obese group (n = 372) vs. obese group (n = 372)). The mean age of the mentioned groups was 67 ± 10 (non-obese group) vs. 66 ± 10 (obese group) years, p = 0.724. All-cause in-hospital mortality did not significantly differ between the groups before PSM (p = 0.566) and after PSM (p = 0.780). The median length of ICU (p = 0.306 before PSM and p = 0.538 after PSM) and hospital stay (p = 0.795 before PSM and p = 0.131 after PSM) was not significantly higher in the obese group compared with the non-obese group. No significant differences regarding further postoperative parameters were observed between the unadjusted and the adjusted group. Obesity does not predict increased all-cause in-hospital mortality in patients undergoing CABG procedure. Therefore, CABG is a safe procedure for overweight patients.

Association of Body Mass Index with Long-Term All-Cause Mortality in Patients Who Had Undergone a Vertebroplasty for a Vertebral Compression Fracture

We aimed to investigate the association between preoperative body mass index (BMI) and postoperative long-term mortality in patients who underwent a vertebroplasty. We retrospectively enrolled patients with a vertebral compression fracture who underwent a vertebroplasty between May 2013 and June 2020 in a medical center in Taiwan. The survival status of the study sample was confirmed by the end of March 2021. Cox-proportional hazard models were conducted to examine the effects of being overweight/obese (≥25 kg/m2 vs. <25 kg/m2) and BMI (as a continuous variable) on all-cause mortality after adjusting for age, sex, history of smoking, diabetes, hypertension, chronic kidney disease, and osteoporosis. A total of 164 patients were analyzed (mean age 75.8 ± 9.3 years, male 25.6%, mean BMI 24.0 ± 4.1 kg/m2) after a median follow-up of 785 days. Compared with a BMI < 25 kg/m2, a BMI ≥ 25 kg/m2 was associated with a significantly lower risk of all-cause mortality (HR 0.297, 95% CI 0.101 to 0.878, p = 0.028). These findings were consistent when BMI was examined as a continuous variable (HR 0.874, 95% CI 0.773 to 0.988, p = 0.031). A low BMI (<22 kg/m2) should be considered as a risk factor for postoperative long-term mortality in this ageing population.

Sarcopaenia, obesity, sarcopaenic obesity and outcomes following hepatic resection for colorectal liver metastases: a systematic review and meta-analysis

BACKGROUND

Obesity is a risk factor for the development of colorectal cancer. Limited evidence exists about outcomes for obese patients undergoing hepatic resection for colorectal liver metastases (CRLM). Sarcopaenia is characterised by a decline in muscle function and muscle mass. It is associated with poorer outcomes for patients on chemotherapy, but there are limited data for sarcopaenic patients undergoing hepatic resection for CRLM.

METHODS

Pubmed, Embase, Cochrane Central, Web of Science, SCOPUS, and CINAHL databases were searched for articles which were selected in accordance with PRISMA guidelines. Primary outcomes were overall survival (OS) and disease-free survival (DFS). A random effects meta-analysis was conducted.

RESULTS

Thirteen studies were included incorporating 2936 patients. No significant difference was found between obese and non-obese patients in OS (HR 0.81, CI 0.47-1.39, p = 0.44) or DFS (HR 1.0, CI 0.99-1.01, p = 0.98). Sarcopaenia was associated with worse OS (HR 1.65, CI 1.10-2.48, p = 0.01), and increased major post operative complications (OR 1.91, CI 1.16-3.14, p = 0.01). Only one study examined outcomes for sarcopaenic obese patients.

CONCLUSION

Limited evidence exists describing the impact of obesity and sarcopenia on outcomes following hepatic resection for CRLM. Obese patients do not have worse oncological outcomes, whereas sarcopaenia is associated with poorer long-term survival.

Protective Role of Obesity on Trauma Impact: A Retrospective Analysis of Patients with Surgical Blunt Bowel Mesenteric Injury Due to Road Traffic Accidents

Background

The "cushion effect" theory proposes that increased body mass index (BMI) is associated with less severe abdomen injury following blunt abdomen trauma, while the "obesity paradox" describes the protective effect of obesity against mortality. However, most previous studies used the abdominal abbreviated injury scale as the outcomes seemed to be inadequate owing to the injuries to the abdominal organs, such as the spleen and liver, which may be attributable to the force that caused the chest trauma. This study aimed to use adult trauma patients with surgical blunt bowel mesenteric injuries (BBMIs) to investigate the influence of obesity on the clinical outcomes and overall morbidities.

Methods

This retrospective study reviewed the data of all hospitalized trauma patients between 2009 and 2019 and included all patients with surgically proven small bowel, colon, or mesenteric injuries due to a road traffic accident. Comparison of the outcomes was performed among 123 patients with surgically proven BBMI, who were categorized by BMI into the normal-weight (n = 73, BMI<25 kg/m²), overweight (n = 37, 25≤BMI≤30 kg/m²), and obese groups (n = 13, BMI>30 kg/m²).

Results

The obese group had a significantly lower incidence of isolated bowel injury (0%) compared with the normal-weight (35.6%) and overweight (16.2%) groups (p=0.005), but with higher incidence of isolated mesenteric injury or combined injury, although this was not significant. The obese group (92.3%) had a significantly higher percentage of overall morbidity than the normal-weight (61.6%) and overweight (70.3%) groups (p = 0.047). No significant difference was observed in the in-hospital mortality and 24-hour mortality among the three study groups.

Conclusion

The study findings do not support the existence of a cushion effect and obesity paradox of obesity in blunt abdominal trauma.

Interaction between donor obesity and prolonged donor ischemic time in heart transplantation

BACKGROUND

The purpose of the study was to determine the impact of donor obesity on outcomes following heart transplantation in the setting of routine (<4 h) and prolonged (≥4 h) organ ischemic times.

METHODS

Retrospective review of the 2000-2020 United Network for Organ Sharing Database was performed to identify adult heart transplant recipients and donors. Nearest-neighbor propensity score matching by donor obesity was performed separately among routine and prolonged cohorts, with Kaplan-Meier survival estimates used to assess survival at 5 years following transplantation.

RESULTS

A total of 43,304 heart transplant recipients were included in analysis, with 15,925 (36.8 %) receiving obese donor hearts. After propensity-score matching, 30-day mortality and 5-year survival following transplantation were not statistically different between recipients of obese and non-obese donor hearts when organ ischemic times were routine. In the setting of prolonged organ ischemic times, those receiving obese donor hearts experienced lower 30-day mortality (5.1 % vs 6.7 %, p = 0.04) and improved 5-year survival (74.9 % vs 71.2 %, p < 0.01) compared to non-obese donor hearts.

CONCLUSIONS

Recipients of obese donor hearts experienced improved outcomes compared to those receiving non-obese donor hearts when organ ischemic times exceeded 4 h. These findings suggest that the detrimental impact of prolonged organ ischemic time may be attenuated by donor obesity.

Association between high preoperative body mass index and mortality after cancer surgery

Despite an association between obesity and increased mortality in the general population, obesity has been paradoxically reported with improved mortality of surgery and some types of cancer. However, this has not been fully investigated in patients undergoing cancer surgery. Using a cohort consisting of mostly Asian population, we enrolled 87,567 adult patients who underwent cancer surgery from March 2010 to December 2019. They were divided into three groups according to body mass index (BMI): 53,980 (61.6%) in the normal (18.5–25 kg/m2), 2,787 (3.2%) in the low BMI (<18.5 kg/m2), and 30,800 (35.2%) in the high BMI (≥25 kg/m2) groups. The high BMI group was further stratified into overweight (25–30 kg/m2) and obese (≥30 kg/m2) groups. The primary outcome was mortality during three years after surgery. Following adjustment by inverse probability weighting, mortality during three years after surgery was significantly lower in the high BMI group than the normal (4.8% vs. 7.0%; hazard ratio [HR], 0.69; confidence interval [CI], 0.64–0.77; p < 0.001) and low BMI (4.8% vs. 13.0%; HR: 0.38; CI: 0.35–0.42; p < 0.001) groups. The mortalities of the overweight and obese groups were lower than that of the normal group (7.0% vs. 5.0%; HR: 0.72; CI: 0.67–0.77; p < 0.001 and 7.0% vs. 3.3%; HR: 0.57; CI: 0.50–0.65; p < 0.001, respectively). This association was not observed in female patients and those undergoing surgery for breast and gynecological cancers. High BMI may be associated with decreased mortality after cancer surgery. Further investigations are needed for clinical application of our finding.

Cardiac surgery in the morbidly obese

BACKGROUND

Obesity rates globally continue to rise and in turn the body mass index (BMI) of patients undergoing cardiac surgery is set to mirror this. Patients who are Class III obese (BMI ≥ 40) pose significant challenges to the surgical teams responsible for their care and are also at high risk of complications from surgery and even death. To improve outcomes in this population, interventions carried out in the preoperative, operative, and postoperative periods have shown promise. Despite this, there are no defined best practice national guidelines for perioperative management of obese patients undergoing cardiac surgery.

AIM

This review is aimed at clinicians and researchers in the field of cardiac surgery and aims to form a basis for the future development of clinical guidelines for the management of obese cardiac surgery patients.

METHODS

The PubMed database was utilized to identify relevant literature and strategies employed at various stages of the surgical journey were analyzed.

CONCLUSIONS

Data presented identified the benefits of preoperative respiratory muscle training, off-pump coronary artery bypass grafting where possible, and early extubation. Further randomized controlled trials are required to identify optimal operative and perioperative management strategies before the introduction of such guidance into clinical practice.

The Metabolic Syndrome Paradox: Increased Morbidity and Decreased Mortality in Operative Orthopedic Trauma

We examined the impact of metabolic syndrome (MetS) on operative outcomes with orthopedic trauma, particularly among patients with pelvic, acetabular, and lower extremity fractures. This retrospective cohort study used the American College of Surgeons National Surgical Quality Improvement Program database to identify patients who had operative pelvic, acetabular, and lower extremity trauma from 2006 through 2014. We defined MetS as type 2 diabetes, a history of hypertension requiring medication, and body mass index of 30 kg/m² or greater. Patients with MetS were compared with unaffected patients and assessed for association with in-hospital complications and mortality. The study population included 37,495 patients; 5.7% (n=2154) had MetS. On multivariable logistic regression, MetS was associated with increased odds of any hospital complication (odds ratio [OR], 1.30; 95% CI, 1.13-1.51; P<.001), Clavien-Dindo grade IV complications (OR, 1.51; 95% CI, 1.23-1.87; P<.001), readmission (OR, 1.39; 95% CI, 1.18-1.63; P<.001), and reoperation (OR, 1.40; 95% CI, 1.11-1.76; P=.004). Conversely, MetS significantly decreased the odds of mortality (OR, 0.67; 95% CI, 0.49-0.92; P=.01). Although MetS is a risk factor for postoperative complications, longer length of stay, and increased readmission after surgical intervention for orthopedic lower extremity trauma, MetS appears to decrease the odds of mortality in this specific patient population, which merits further investigation. [Orthopedics. 2022;45(2):103-108.].

Epidemiology of Obese Patients Undergoing Revision Total Knee Arthroplasty: Understanding Demographics, Comorbidities, and Propensity Weighted Analysis of Inpatient Outcomes

INTRODUCTION

Obesity is a public health epidemic that is projected to grow in coming years. Observational data on the epidemiologic profile and immediate postoperative outcomes of obesity and morbid obesity after revision total knee arthroplasty (rTKA) are limited.

METHODS

Discharge data from the National Inpatient Sample was used to identify patients who underwent rTKA from 2006 to 2015. Patients were stratified into morbidly obese, obese, and not obese control cohorts. An analysis was performed to compare etiology of revision, demographic and medical comorbidity profiles, and immediate in-hospital economic and complication outcomes after rTKA.

RESULTS

An estimated 605,603 rTKAs were included in this analysis. Morbidly obese and obese patients were at significantly higher risk for any complication than not obese patients. Patients with obesity were associated with an increased risk of postoperative anemia but a lower risk of peripheral vascular disease and gastrointestinal, and hematoma/seroma complications compared with not obese patients. Patients with morbid obesity were associated with an increased risk of any, hematoma/seroma, wound dehiscence, postoperative infection, pulmonary embolism, and postoperative anemia complications and a lower risk of gastrointestinal complications when compared with not obese patients. Morbidly obese patients had a significantly longer length of stay than both obese and not obese patients, while no significant difference in length of stay was observed between obese and not obese patients.

DISCUSSION

Morbidly obese patients are at higher odds for worse postoperative medical and economic outcomes compared with those with obesity after rTKA. As the number of patients with obesity and morbid obesity continues to rise, these risk factors should be considered in preoperative discussions and perioperative protocol optimization.

Effect of weight-loss diets prior to elective surgery on postoperative outcomes in obesity: A systematic review and meta-analysis

This systematic review investigated the effects of weight-loss diets before elective surgery on preoperative weight loss and postoperative outcomes in people with obesity. Electronic databases were searched from inception to May 2021. Inclusion criteria were prospective cohort or randomised controlled studies that compared effects of weight-loss diets to standard care on postoperative outcomes in adults with obesity awaiting surgery. Participants with cancer or undergoing bariatric surgery were excluded. Data on preoperative weight change, length of stay, postoperative complications and patient-reported outcome measures were extracted and synthesised in meta-analyses. One randomised controlled trial involving total knee arthroplasty and two that investigated general surgery were eligible that included 173 participants overall. Each study compared low-calorie diets using meal replacement formulas to usual care. There is very-low-quality evidence of a statistically significant difference favouring the intervention for preoperative weight loss (mean difference [MD] -6.67 kg, 95% confidence interval [CI] -12.09 to -1.26 kg; p = 0.02) and low-quality evidence that preoperative weight-loss diets do not reduce postoperative complications to 30 days (odds ratio [OR] 0.34, 95% CI 0.08-1.42; p = 0.14) or length of stay (MD -3.72 h, 95% CI -10.76 to 3.32; p = 0.30). From the limited data that is of low quality, weight loss diets before elective surgery do not reduce postoperative complications.

The Association of Body Mass Index with Outcomes after Carotid Endarterectomy

BACKGROUND

Patients who are obese or underweight are traditionally at higher risk for perioperative morbidity and mortality. The effect of body mass index (BMI) on outcomes after carotid endarterectomy (CEA) is unclear. Our goal was to analyze the association of BMI with perioperative and long-term outcomes after elective CEA.

METHODS

The Vascular Quality Initiative (VQI) database was queried from 2003-2018 for patients undergoing elective CEAs. Patients were categorized into 5 BMI cohorts - underweight (UW, BMI < 18.5 kg/m²), normal weight (NW, BMI 18.5-24.9 kg/m²), overweight (OW, BMI 25-29.9 kg/m²), obese (OB, BMI 30-39.9 kg/m²), and morbidly obese (MO, BMI ≥ 40 kg/m²). Perioperative and long-term outcomes were assessed with univariable and multivariable analyses.

RESULTS

There were 89,079 patients included: 2% UW, 26% NW, 38.4% OW, 29.9% OB, and 3.6% MO. Overall, the mean age was 70.6 years, 60% were male, and 91.8% were of white race. There were significant differences among the BMI cohorts in regards to age, sex, smoking status, and comorbidities (all P < 0.05). For perioperative outcomes, the BMI cohorts differed significantly in reoperation for bleeding and 30-day mortality. On multivariable analysis, BMI was not associated with stroke or perioperative mortality. MO was associated with perioperative cardiac complications (Odds Ratios [OR] 1.26, 95% CI 1-1.57, P = 0.05). UW status was associated with increased return to the operating room (OR 1.89, 95% confidence interval [95% CI] 1.28-2.78, P = 0.001), 30-day mortality (OR 1.68, 95% CI 1-2.86, P =0.05), 1-year mortality (Hazard ratio [HR] 1.37, 95% CI 1.08-1.74, P = 0.01), and 5-year mortality (HR 1.22, 95% CI 1.06-1.41, P =0.005).

CONCLUSIONS

BMI status was not associated with perioperative stroke, cranial nerve injury, or surgical site infections. Patients with MO had higher perioperative cardiac complications. UW patients have lower short and long-term survival and should be a focus for long-term targeted risk factor stratification and modification.

Does "obesity paradox" apply for patients undergoing transcatheter aortic valve replacement?

BACKGROUND

Data is controversial regarding the existence of an "obesity paradox" in patients undergoing Transcatheter Aortic Valve Replacement (TAVR). We sought to investigate the prognostic value of the body mass index (BMI) on outcomes following TAVR.

METHODS

This is an observational, single-center study involving all patients who underwent TAVR from 2009 to 2019. BMI was calculated in all patients before TAVR. The cohort was subdivided into four groups: underweight (<20 kg/m²), normal weight (≥20 to <25 kg/m²), overweight (≥25 to <30 kg/m²) and obese (≥30 kg/m²). The main endpoint was all-cause 30-day and one-year mortality.

RESULTS

A total of 412 patients (mean age 79.6 ± 7.8 years, mean STS score 5.3 ± 3.6) were included. Patients were grouped as follows: underweight (n = 35, 8.5%), normal weight (n = 121, 29.4%), overweight (n = 140, 34%) and obese (n = 116, 28.1%). Obese patients were younger, included more females and had lower STS score than the rest of the cohort whereas underweight patients were older, had higher STS score, more chronic kidney disease, more left ventricular dysfunction and more often underwent non-transfemoral TAVR. BMI predicted 30-day survival (AUC:0.692 [95%CI 0.522-0.862]; p = 0.030) with an optimal cut-off of 24.4 (sensitivity = 66.6%, specificity = 63.6%). On multivariate analysis, higher BMI trended toward lower 30-day mortality (HR = 0.87 [95%CI 0.75-1.01]; p = 0.071). Thirty-day mortality was higher in the underweight group (8.3%) in comparison with other BMI subgroups (normal weight 2.5%, overweight 1.4%, obese 0.9%; p = 0.045). However, no significant difference was found after adjustment of confounders (all p = NS). BMI did not predict one-year mortality. No significant difference in one-year survival was observed between the four BMI subgroups (log rank p = 0.925).

CONCLUSION

BMI could represent an interesting prognostic tool for short-term mortality in patients undergoing TAVR. BMI < 20 kg/m² was associated with higher 30-day mortality. Symptoms improved similarly in obese patients compared to lower BMI patients. For 30-day survivors, no evidence of the existence of an obesity paradox was observed in this cohort.

Total Laparoscopic Hysterectomy: Making It Safe and Successful for Obese Patients

Objective

To investigate outcomes and ascertain the safety and efficacy on patients having total laparoscopic hysterectomy (TLH), stratified by body mass index (BMI), focusing on high-BMI patients.

Methods

This was a retrospective cohort study that reviewed 2,266 patients with benign gynecologic diagnoses, early cervical, endometrial, and ovarian carcinoma from September 1996 to October 2017. BMI was from 14.5 to 74.2 and were classified as normal or underweight (<24.9); overweight (25.0-29.9); class I obese (>30.0-34.9); class II obese (35-39.9); or class III obese (>40.0). All patients underwent TLH.

Results

Patients' characteristics were similar across all BMI classes except for age, postoperative pathological diagnoses, and whether a cystoscopy was performed. Surgical duration, and estimated blood loss were similar across BMI classes. Overweight and obese class III patients had lower odds of staying >1 day compared to patients of normal BMI (OR = 0.65, P = .015). Obese class II patients had fewer complications compared to normal BMI patients (OR = 0.27, P = .013), but patients from other high BMI categories did not show any difference compared to patients with normal BMI. The rate of unplanned laparotomy was statistically, but not clinically, higher in obese class III patients (1.8% versus .7%, P = 0.011), most often due to large fibroids. The mean reoperation rate was 2.7%, with the lowest rate (.5%) among obese class II patients, and the highest rate (3.9%) among the normal BMI patients.

Conclusion

TLH is feasible and safe for obese women, regardless of BMI. Obesity is not a contraindication to good outcomes from laparoscopic surgery.

Complications and 30-Day Mortality Rate After Hip Fracture Surgery in Superobese Patients

OBJECTIVE

Paradoxically, overweight and obesity are associated with lower odds of complications and death after hip fracture surgery. Our objective was to determine whether this "obesity paradox" extends to patients with "superobesity." In this study, we compared rates of complications and death among superobese patients with those of patients in other body mass index (BMI) categories.

METHODS

Using the National Surgical Quality Improvement Program database, we identified >100,000 hip fracture surgeries performed from 2012 to 2018. Patients were categorized as underweight (BMI <18.5), normal weight (BMI 18.5-24.9), overweight (BMI 25-29.9), obese (BMI 30-39.9), morbidly obese (BMI 40-49.9), or superobese (BMI ≥50). We analyzed patient characteristics, surgical characteristics, and 30-day outcomes. Using multivariate regression with normal-weight patients as the referent, we determined odds of major complications, minor complications, and death within 30 days by BMI category.

RESULTS

Of 440 superobese patients, 20% had major complications, 33% had minor complications, and 5.2% died within 30 days after surgery. When comparing patients in other BMI categories with normal-weight patients, superobese patients had the highest odds of major complications [odds ratio (OR): 1.6, 95% confidence interval (CI), 1.2-2.0] but did not have significantly different odds of death (OR: 0.91, 95% CI, 0.59-1.4) or minor complications (OR: 1.2, 95% CI, 0.94-1.4).

CONCLUSION

Superobese patients had significantly higher odds of major complications within 30 days after hip fracture surgery compared with all other patients. This "obesity paradox" did not apply to superobese patients.

LEVEL OF EVIDENCE

Prognostic Level III. See Instructions for Authors for a Complete Description of Levels of Evidence.

Anesthetic management for robotic hysterectomy in obese women

PURPOSE OF REVIEW

Obesity is a major health epidemic, with the prevalence reaching ∼40% in the United States in recent years. It is associated with increased risk of hypertension, diabetes, heart disease, stroke, obstructive sleep apnea (OSA), and gynecologic conditions requiring surgery. Those comorbidities, in addition to the physiologic changes associated with obesity, lead to increased risk of perioperative complications. The purpose of this review is to highlight the anesthetic considerations for robotic assisted hysterectomy in obese patients.

RECENT FINDINGS

In the general gynecologic population, minimally invasive surgery is associated with less postoperative fever, pain, hospital length of stay, total cost of care and an earlier return to normal function. This also applies to robotic surgery in obese patients, which is on the rise. The physiologic changes of obesity bring different anesthetic challenges, including airway management and intraoperative ventilation. Vascular access and intraoperative blood pressure monitoring can also be challenging and require modifications. Optimizing analgesia with a focus on opioid-sparing strategies is crucial due to the increased prevalence of OSA in this patient population.

SUMMARY

Anesthesia for obese patients undergoing robotic hysterectomy is challenging and must take into consideration the anatomic and physiologic changes associated with obesity.

The Obesity Paradox in Elderly Patients Undergoing Emergency Surgery: A Nationwide Analysis

BACKGROUND

Obesity has long been considered a risk factor for postoperative adverse events in surgery. We sought to study the impact of body mass index (BMI) on the clinical outcomes of the high-risk emergency general surgery (EGS) elderly patients.

METHODS

All EGS ≥65 years old patients in the 2007-2016 ACS-NSQIP database, identified using the variables 'emergency' and 'surgspec,' were included. Patients were classified into five groups: normal weight: BMI <25 kg/m², overweight: BMI ≥25 kg/m² and <30 kg/m², Class I: BMI ≥30 kg/m² and <35 kg/m², Class II: BMI ≥35 kg/m² and <40 kg/m², and Class III: BMI ≥40 kg/m². Patients with BMI<18.5 kg/m² were excluded. Multivariable logistic regression models were built to assess the relationship between obesity and 30-day postoperative mortality, overall morbidity, and individual postoperative complications after adjusting for demographics (e.g., age, gender), comorbidities (e.g., diabetes mellitus, heart failure), laboratory tests (e.g., white blood cell count, albumin), and operative complexity (e.g., ASA classification).

RESULTS

A total of 78,704 patients were included, of which 26,011 were overweight (33.1%), 13,897 (17.6%) had Class I obesity, 5904 (7.5%) had Class II obesity, and 4490 (5.7%) had Class III obesity. On multivariable analyses, compared to the nonobese, patients who are overweight or with Class I-III obesity paradoxically had a lower risk of mortality, bleeding requiring transfusion, pneumonia, stroke and myocardial infarction (MI). Additionally, the incidence of MI and stroke decreased in a stepwise fashion as BMI progressed from overweight to severely obese (MI: OR: 0.84 [0.73-0.95], OR: 0.73 [0.62-0.86], OR: 0.66 [0.52-0.83], OR: 0.51 [0.38-0.68]; stroke: OR: 0.80 [0.65-0.99], OR: 0.79 [0.62-1.02], OR: 0.71 [0.50-1.00], OR: 0.43 [0.28-0.68]).

CONCLUSION

In our study of elderly EGS patients, overweight and obese patients had a lower risk of mortality, bleeding requiring transfusion, pneumonia, reintubation, stroke, and MI. Further studies are needed to confirm and investigate the obesity paradox in this patient population.

Association Between High Body Mass Index and Mortality Following Myocardial Injury After Noncardiac Surgery

BACKGROUND

Despite an association between obesity and increased risks for various diseases, obesity has been paradoxically reported to correlate with improved mortality in patients with established cardiovascular disease. However, its effect has not been evaluated to date in patients with myocardial injury after noncardiac surgery (MINS).

METHODS

From January 2010 to June 2019, of a total of 35,269 adult patients with postoperative cardiac troponin level data, 5633 (16.0%) patients had MINS as diagnosed by postoperative cardiac troponin I above the 99th-percentile upper reference of 40 ng·L-1 using the TnI-Ultra immunoassay. Patients with MINS were divided into 3 groups according to body mass index (BMI), with 3246 (57.6%) were in the normal (18.5-25 kg·m-2), 425 (7.5%) in the low BMI (<18.5 kg·m-2), and 1962 (34.8%) in the high BMI (≥25 kg·m-2) groups, respectively. The primary outcome was mortality during the first year after surgery, and the mortality during 30 days was also compared.

RESULTS

Following adjustment for confounding with inverse probability of treatment weighting, mortality within the first year appeared to be significantly lower in the high BMI group compared with the normal (14.8% vs 20.9%; hazard ratio [HR], 0.75; 95% confidence interval [CI], 0.66-0.85; P < .001) and the low BMI (14.8% vs 25.6%; HR: 0.56; 95% CI, 0.48-0.66; P < .001) groups.

CONCLUSIONS

High BMI may be associated with decreased mortality following MINS. Further investigations are needed to support this finding.

The prognostic value of modified NUTRIC score for patients in cardiothoracic surgery recovery unit: A retrospective cohort study

BACKGROUND

Malnutrition is highly prevalent in critically ill patients. The modified Nutrition Risk in the Critically ill (mNUTRIC) score has been introduced to evaluate the nutritional risk of patients in an intensive care unit (ICU). The mNUTRIC score is a predictive factor of mortality for patients in a medical or mixed ICU, whereas the relationship between mNUTRIC and prognosis of patients in a cardiothoracic surgery recovery unit (CSRU) is unclear and related researches are limited.

METHODS

We conducted this retrospective cohort study to explore the value of mNUTRIC score in CSRU patients. We identified totally 4059 patients from the Multiparameter Intelligent Monitoring in Intensive Care III (MIMIC III) database.

RESULTS

The optimal cut-off value of mNUTRIC score was 4 and a total of 1498 (36.9%) patients were considered to be at high nutritional risk (mNUTRIC ≥ 4). A multivariate logistic regression model indicated that patients at high nutritional risk have higher hospital mortality compared to those at low nutritional risk (odds ratio = 2.49, 95% confidence interval (CI) = 1.32-4.70, p = 0.005]. Furthermore, a Cox regression model was established adjusted for age, white blood cell and body mass index. The Kaplan-Meier curve indicated that patients at high nutritional risk have poorer 365-days [hazard ratio (HR) = 1.76, 95% CI = 1.30-2.37, p < 0.001] and 1000-days (HR = 2.30, 95% CI = 1.87-2.83, p < 0.001) overall survival.

CONCLUSIONS

The mNUTRIC score could not only predict hospital mortality, but also be an independent prognostic factor for long-term survival in CSRU patients. More well-designed clinical trials are needed to verify and update our findings.

The Obesity Paradox in Emergency General Surgery Patients

Operative management of emergency general surgery (EGS) diagnoses involves a range of procedures which can carry high morbidity and mortality. Little is known about the impact of obesity on patient outcomes. The aim of this study was to examine the association between body mass index (BMI) >30 kg/m² and mortality for EGS patients. We hypothesized that obese patients would have increased mortality rates.

A regional integrated health system EGS registry derived from The American Association for the Surgery of Trauma EGS ICD-9 codes was analyzed from January 2013 to October 2015. Patients were stratified into BMI categories based on WHO classifications. The primary outcome was 30-day mortality. Longer-term mortality with linkage to the Social Security Death Index was also examined. Univariate and multivariable analyses were performed.

A total of 60 604 encounters were identified and 7183 (11.9%) underwent operative intervention. Patient characteristics include 53% women, mean age 58.2 ± 18.7 years, 64.2% >BMI 30 kg/m², 30.2% with chronic obstructive pulmonary disease, 19% with congestive heart failure, and 31.1% with diabetes. The most common procedure was laparoscopic cholecystectomy (36.4%). Overall, 90-day mortality was 10.9%. In multivariable analysis, all classes of obesity were protective against mortality compared to normal BMI. Underweight patients had increased risk of inpatient (OR = 1.9, CI = 1.7-2.3), 30-day (OR = 1.9, CI = 1.7-2.1), 90-day (OR = 1.8, CI 1.6-2.0), 1-year (OR = 1.8, CI = 1.7-2.0), and 3-year mortality (OR = 1.7, CI = 1.6-1.9).

When stratified by BMI, underweight EGS patients have the highest odds of death. Paradoxically, obesity appears protective against death, even when controlling for potentially confounding factors. Increased rates of nonoperative management in the obese population may impact these findings.

Association of intraoperative hypothermia with oncologic outcomes following radical cystectomy

INTRODUCTION

Intraoperative hypothermia (IOH) has been suggested to adversely impact outcomes following surgery. The objective of this study was to evaluate the association between IOH and survival following radical cystectomy (RC).

METHODS

Patients who underwent RC for bladder cancer from 2003 to 2018 were identified in our cystectomy registry. Intraoperative temperatures were extracted from the anesthesia record. IOH was defined as a median intraoperative temperature <36°C, and severe IOH as ≤ 35°C. Time under 36°C was assessed as a continuous variable. Recurrence-free survival (RFS), cancer-specific survival (CSS), and overall survival (OS) were estimated using the Kaplan-Meier method. Associations between IOH and outcomes were assessed with multivariable Cox proportional hazards models.

RESULTS

A total of 852 patients were identified, among whom 274 (32%) had IOH. Median follow up among survivors was 4.9 years (IQR 2.4-8.7), during which time 483 patients died, including 343 from bladder cancer. Two-year survival was not significantly different between patients with and without IOH (CSS: 74% vs. 71%, P= 0.31; OS: 68% vs. 67%, P= 0.13). Following multivariable adjustment, neither IOH nor time under 36°C was significantly associated with survival. A total of 37 patients (4.3%) had severe IOH. These patients were observed to have significantly lower 2-year OS (56% vs. 68%, P= 0.005); however, this association did not remain statistically significant after multivariable adjustment (P= 0.92).

CONCLUSION

IOH was not independently associated with survival following RC. These data do not support IOH as a prognostic factor for cancer outcomes among patients undergoing RC.

Does Weight Matter? Outcomes in Adult Patients on Venovenous Extracorporeal Membrane Oxygenation When Stratified by Obesity Class

BACKGROUND

Many believe obesity is associated with higher rates of mortality in the critically ill. The purpose of this retrospective observational study is to evaluate the association between body mass index (BMI) and survival in patients receiving venovenous (VV) extracorporeal membrane oxygenation (ECMO) for acute hypoxic or hypercarbic respiratory failure.

METHODS

All of the patients admitted to a dedicated VV ECMO unit were included. Patients <18 years of age, listed for lung transplant, or underweight were excluded. ECMO outcomes, including hospital length of stay and survival to discharge, were analyzed after stratification according to BMI. Multivariate logistic and linear regression techniques were used to assess variables associated with the outcomes of death and length of stay, respectively.

RESULTS

One hundred ninety-four patients with a median BMI of 35.7 kg/m (33-42 kg/m) were included. Obese patients were older, had higher creatinine levels, and required higher levels of positive end-expiratory pressure and mean airway pressure at time of cannulation. Survival to discharge in any group did not differ when stratified by BMI classification (P = .36). Multivariable regression did not reveal any association with greater odds of death or longer length of stay when controlling for BMI and other variables.

CONCLUSIONS

We did not detect an association between obesity and increased mortality in patients requiring VV ECMO for acute hypoxic or hypercarbic respiratory failure. These data suggest that obesity alone should not exclude candidacy for VV ECMO. Evidence for the "obesity paradox" in this population of VV ECMO patients may be supported by these data.

The effect of body mass index on outcomes following severe blunt chest trauma

INTRODUCTION

Obesity has been described as a significant risk factor for adverse outcomes in hospitalized patients. However, recent literature reports an "obesity paradox", suggesting that obesity may have a protective effect in a subset of surgical and critically ill patients. The present study assesses the effect of body mass index (BMI) on outcomes following severe isolated blunt chest trauma.

METHODS

This was a TQIP database study including patients with severe isolated blunt chest injury (chest AIS 3-5, extrathoracic AIS <3). Patients were excluded for age <20 or >89, death on arrival, facility transfer, or BMI <10 or >55. Patients were divided into five groups according to BMI: underweight (BMI <18.5), normal weight (18.5-24.9), overweight (25.0-29.9), obesity class 1 (30.0-34.9), obesity class 2 (35.0-39.9) and obesity class 3 (≥40.0). Logistic regression models were constructed to evaluate the effect of BMI on outcomes.

RESULTS

28,820 patients met criteria for inclusion in the analysis. After multivariable analysis, underweight patients as well as obesity class 2 and 3 patients had a significantly higher mortality (OR 1.86 [95% CI, 1.12-3.10], OR 1.48 [95% CI, 1.02-2.16], and OR 1.60 [95% CI, 1.03-2.50]), respectively. Underweight patients had significantly higher risk of overall complications as compared to normal weight patients (OR 1.58 [95% CI, 1.34-1.88]). Obesity class 2 and 3 were independently associated with increased respiratory complications (OR 1.60 [95% CI, 1.27-2.01] and OR 1.58 [95% CI, 1.20-2.09], respectively) and all classes of overweight and obese patients were associated with increased risk of VTE complications (OR 1.68 [95% CI, 1.23-2.27], OR 1.98 [95% CI, 1.42-2.77], OR 2.32 [95% CI, 1.55-3.48], OR 2.02 [95% CI, 1.23-3.33], respectively for overweight and obesity class 1, 2, 3).

CONCLUSIONS

The obesity paradox does not extend to severe blunt chest trauma. Underweight and obesity class 2 and 3 patients have worse mortality than normal weight patients. Obesity was independently associated with an increased risk of pulmonary and VTE complications.

Isolated severe blunt traumatic brain injury: effect of obesity on outcomes

OBJECTIVE

Obesity has been widely reported to confer significant morbidity and mortality in both medical and surgical patients. However, contemporary data indicate that obesity may confer protection after both critical illness and certain types of major surgery. The authors hypothesized that this "obesity paradox" may apply to patients with isolated severe blunt traumatic brain injuries (TBIs).

METHODS

The Trauma Quality Improvement Program (TQIP) database was queried for patients with isolated severe blunt TBI (head Abbreviated Injury Scale [AIS] score 3-5, all other body areas AIS < 3). Patient data were divided based on WHO classification levels for BMI: underweight (< 18.5 kg/m2), normal weight (18.5-24.9 kg/m2), overweight (25.0-29.9 kg/m2), obesity class 1 (30.0-34.9 kg/m2), obesity class 2 (35.0-39.9 kg/m2), and obesity class 3 (≥ 40.0 kg/m2). The role of BMI in patient outcomes was assessed using regression models.

RESULTS

In total, 103,280 patients were identified with isolated severe blunt TBI. Data were excluded for patients aged < 20 or > 89 years or with BMI < 10 or > 55 kg/m2 and for patients who were transferred from another treatment center or who showed no signs of life upon presentation, leaving data from 38,446 patients for analysis. Obesity was not found to confer a survival advantage on univariate analysis. On multivariate analysis, underweight patients as well as obesity class 1 and 3 patients had a higher rate of mortality (OR 1.86, 95% CI 1.48-2.34; OR 1.18, 95% CI 1.01-1.37; and OR 1.41, 95% CI 1.03-1.93, respectively). Increased obesity class was associated with an increased risk of respiratory complications (obesity class 1: OR 1.19, 95% CI 1.03-1.37; obesity class 2: OR 1.30, 95% CI 1.05-1.62; obesity class 3: OR 1.55, 95% CI 1.18-2.05) and thromboembolic complications (overweight: OR 1.43, 95% CI 1.16-1.76; obesity class 1: OR 1.45, 95% CI 1.11-1.88; obesity class 2: OR 1.55, 95% CI 1.05-2.29) despite a decreased risk of overall complications (obesity class 2: OR 0.82, 95% CI 0.73-0.92; obesity class 3: OR 0.83, 95% CI 0.72-0.97). Underweight patients had a significantly increased risk of overall complications (OR 1.39, 95% CI 1.24-1.57).

CONCLUSIONS

Although there was an obesity-associated decrease in overall complications, the study data did not demonstrate a paradoxical protective effect of obesity on mortality after isolated severe blunt TBI. Obese patients with isolated severe blunt TBI are at increased risk of respiratory and venous thromboembolic complications. However, underweight patients appear to be at highest risk after severe blunt TBI, with significantly increased risks of morbidity and mortality.

Adjusted preoperative variables to predict perioperative red blood cell transfusion in coronary artery bypass grafting

BACKGROUND

The variables for predicting blood transfusion perioperatively are not completely clear in coronary artery bypass grafting (CABG) patients.

OBJECTIVES

To construct a comprehensive model to predict perioperative RBC transfusion in patients undergoing isolated CABG using adjusted preoperative variables.

METHODS

Perioperative data of 1253 patients who underwent isolated CABG by the same surgical team were collected from April 2018 to March 2019. Logistic regression analyses were used to establish equations to construct two models for predicting intraoperative and postoperative RBC transfusions, respectively. All significant variables included in the two models were combined to form a comprehensive model to predict perioperative RBC transfusion. Area under the receiver operating characteristic (ROC) curve (AUC) was used to evaluate the discriminatory power of the models.

RESULTS

The total RBC transfusion rate for CABG patients during hospitalization was 29.05%. The rate of intraoperative and postoperative RBC transfusions was 6.9% and 26.7%, respectively. Eight variables in a total of 30 risk factors constituted the intraoperative prediction model, 12 variables constituted the postoperative prediction model, and 13 variables for the combined model. The AUC of the three models were 0.87, 0.82, and 0.83, respectively, demonstrating moderate discriminatory power for RBC transfusion during the intraoperative, postoperative, and perioperative periods.

CONCLUSION

The comprehensive model combined with all variables of predicting intraoperative and postoperative RBC transfusion is feasible for predicting perioperative RBC transfusion.

The BMI Paradox and Robotic Assisted Partial Nephrectomy

Introduction: Partial nephrectomy (PN), has become the gold standard for the surgical management of small renal masses, due to excellent oncologic control with concomitant preservation of nephron units. However, data regarding the association of obesity with perioperative outcomes following PN are mixed. Therefore, the association between obesity (using BMI) and post-operative complications (POC) rate following Robotic assisted laparoscopic PN (RPNx) was tested.

Methods: Two hundred and fifty-one adult patients who underwent RPNx from 1/2011 to 5/2017 at a single institution, with at least 90 days follow-up were identified and included. No patients were excluded. Electronic medical records were reviewed to record all POC within 90 days of surgery. A piecewise generalized linear model for binary outcomes (logistic) was used to model the proportion of subjects with POC by their BMI. The slope of the line is adjusted to a BMI of 30 Kg/m².

Results: BMI is significantly associated with POC rate. POC rate decreased with increasing BMI below the inflection point of 30 Kg/m² (0.848[0.756, 0.952]) (OR [95% CI], p = 0.005). POC rate was found to increase with increasing BMI above the BMI inflection of 30 Kg/m² (1.102 [1.027, 1.182], p = 0.0071).

Conclusions: In this cohort study, BMI showed an association with PC. It may be important to take BMI into account in surgical and clinical management considerations of RPNx, since higher rates of POC are associated with patients who are underweight, morbidly obese, and even with normal BMI. Further research is required on larger cohorts of RPNx patients to provide better description of this phenomenon and elucidate the role of BMI in development of POC.